Lanczos reduction techniques for electric field reflection

It is shown that Lanczos reduction can be employed to analyze reflection at the interface between two inhomogeneous refractive index media. Although generally less accurate than split-operator techniques, the method is convergent for a relatively small number of Lanczos functions if modes with near cutoff propagation constants are not appreciably excited. A substantial compensating advantage in comparison to other approximate techniques, however, is that the model structure of the reflected electric field is obtained with a reasonable degree of precision, and the power flux, therefore, can be simply and very rapidly determined